how many work is needed to stop a 20g bullet moving witi speed of 150ms'1

Answer 1

mass = m = 20 g = 20 / 1000 = 0.02 kg

speed = v = 150m/s

The workdone to stop bullet must be equal to its kinetic energy:

W = m v ^ 2 / 2

W = 0.02 * 150 ^ 2 / 2 =

0.02 * 22500 / 2 =

450 / 2 = 225 J

225 Joules